The differences with the OS are minimal, if anything a few Palm apps have been updated and run more stable. Please, for anyone reading this entry, I am just mentioning OS changes, not phone criticism (that is way developed in other post entries):

- For GSM versions only, the phone application was changed to make it more user-friendly and looks very nice, I am not too sold on the usability though but is a change. For CDMA versions it is the exact same app that is in the 650.

- Other minor detail: When you leave the home button pressed, a small "screen" will pop up with the last 10 apps you have opened.

- Blazer is more stable, but you do have the occasional resets when browsing the web.

- The LED operation changes by carrier and by application. As an example, Sprint's 700p LED while connected did not flash green, but Verizon's version did. You are better off understanding what LED behavior to expect out of the box reading the online AT&T manual.

- You have more options for ringtones, and the phone app now supports MP3 ringtones without 3rd party apps though not quite in a straightforward fashion (look for making ringtones in the 700p forum and you'll see how/why)

- Versamail has Exchange support built-in. I understand that Versamail is not 100% part of the OS, but since it comes bundled it is worth mentioning it.

- The Bluetooth stack changed, but it is hard to say if it did for good or bad. Hands-free devices that worked before with a 650 may not work with the newest Treos.

- The power-management seems to be worse than before. Perhaps is more a hardware issue than a software issue, but no device that runs in the latest Garnet flavor is able to compare battery life with the 650 with its old garnet flavor.

- A handfull of apps don't run in the latest Treos. Most of the important and popular ones have been patched or updated to support latest Garnet OS.

That's from the top of my head.

Ode to the Treo Pro: you had to look so good, you had to be HTC in disguise...